JP4458167B2 - External surface lubrication method in seamless pipe manufacturing using hot plastic working lubricant. - Google Patents

Description

The present invention relates to a lubricant for reducing friction between a workpiece in a hot working apparatus and a contact member therewith and preventing seizure, more specifically, a drilling machine for a seamless pipe manufacturing apparatus. reduce the guide shoe or the like and the friction between the workpiece, about an outer surface lubrication method in seamless pipe production using the hot plastic working lubricant to prevent seizure.

  For example, when the seamless steel pipe is manufactured by the Mannesmann method, the billet is punched by a piercing machine (piercer), and is subjected to stretching rolling such as mandrel mill rolling and constant diameter rolling such as stretch reducing rolling.

  When a billet is drilled by a punching machine (piercer), a guide shoe is used to prevent the billet outer diameter from increasing more than necessary, and the billet is processed with its outer surface in contact with the guide shoe. Therefore, if the lubrication between the outer surface of the billet and the guide shoe is poor, not only seizure flaws occur on the guide shoe itself, but also the outer surface of the perforated raw tube (hereinafter referred to as hollow shell) is called a shoe mark. A seizure defect occurs.

  There are two types of guide shoes: a fixed plate type and a rotary disk type. When using either type of guide shoe, the billet outer surface is used to prevent the above seizure. It is very important to maintain good lubrication with the guide shoe. Several proposals have been made for this lubrication method as follows.

  For example, Patent Document 1 discloses a piercing and rolling method in which a mixed paint of a seizure inhibitor made of metal oxide powder and a binder is applied.

  Patent Document 2 discloses a stainless steel hot rolling lubricant containing iron oxide powder, an acrylic acid-based water-soluble polymer, and a surfactant.

  Patent Document 3 discloses a hot working lubricant containing iron oxide, sodium silicate, starches, and xanthan gum.

  Further, Patent Document 4 includes an aqueous solution comprising an aqueous solution containing a metal oxide powder and sodium silicate and having a viscosity of 200 cp or more and less than 4000 cp, and is spray coated on the surface of a heated hot rolled material. Pipe rolling lubricants are described.

  However, the lubricants disclosed in these documents cannot sufficiently reduce the friction between the guide shoe and the hollow shell, especially when used when drilling difficult-to-work materials such as 13% Cr steel. The effect of preventing sputum generation is not always sufficient.

  Furthermore, Patent Document 5 describes a method of rolling while mixing and supplying a solid lubricant to a swollen mica aqueous solution between a material to be rolled and a guide shoe. However, the lubricant disclosed in this document has a problem of bumping and peeling off at the time of application, and the effect of preventing seizure is not sufficient.

JP 60-21111 A JP-A-7-126684 JP 11-35967 A Japanese Patent No. 2638317 Japanese Unexamined Patent Publication No. 7-284817

  A lubricant for hot plastic working is required to have sufficient lubricity to prevent seizure. In addition, the lubricant must be able to be supplied smoothly to the necessary places when used. That is, it is also required that the supply property is good. Furthermore, even if the lubricant remains on the surface of the product after processing, its corrosion resistance and the like must not be impaired.

The object of the present invention is a heat that is particularly excellent in supply and lubricity, can be sufficiently adhered even if scale is present on the surface of the work material, and is efficiently supplied to the drilling machine and exhibits sufficient lubricity. used during plastic working lubricant is to provide an outer surface lubrication in excellent characteristics seamless pipe production which can sufficiently exert the lubricant.

Gist of the present invention is the outer surface lubrication in seamless pipe production (II) below using a hot plastic working lubricant for the following (I).

(I) A lubricant for hot plastic working, containing 25 to 35 % by mass of iron oxide and 15 to 25 % by mass of sodium silicate, impurities of 3% by mass or less, and moisture of 42 to 57% by mass % (Provided that the total mass of the lubricant is 100%).

The “impurities” refer to zinc oxide (ZnO), lead oxide (PbO), and copper oxide (CuO). In the process of preparing the lubricant of the present invention, since these oxides are particularly likely to be mixed and have a great influence on the performance of the lubricant, the respective contents of zinc oxide, lead oxide and copper oxide, or these oxides The upper limit of the total content of two or more of was prescribed.

  As described above, this lubricant is a lubricant for hot plastic working in which iron oxide powder is dispersed in sodium silicate (water glass) and contains moisture as an essential constituent.

  In addition to the above components, in order to improve the dispersibility stability of the iron oxide powder, naphthalene sulfonic acid soda formalin condensate, styrene / maleic anhydride copolymer soda salt, polyacrylic acid soda salt, polyethylene, etc. Substances such as glycol alkyl ether and polyethylene glycol alkyl phenyl ether may be added as a stabilizer. The amount added is preferably about 20 to 100 grams per liter of lubricant.

  The lubricant of the present invention is used particularly in the production of seamless pipes made of steel containing 8 to 25% by mass of Cr, for example, SUS420H equivalent steel, SUS304 equivalent steel, or 25Cr duplex stainless steel. It is suitable for.

(II) An outer surface lubrication method in seamless pipe manufacturing, wherein the hot plastic working lubricant according to (I) is directly applied to the outer surface of a workpiece within 1 second before the start of piercing and rolling.

  The lubricant for hot plastic working of the present invention is excellent in lubricity and exhibits a remarkable effect in preventing seizure. Moreover, the supply property of the lubricant is good, and the corrosion resistance of the product is not adversely affected. Since the lubricant of the present invention is excellent in adhesion to the heated high-temperature workpiece surface, it is possible to supply (apply) the lubricant to the high-temperature workpiece surface and other difficult-to-supply parts. Furthermore, just before piercing and rolling, the lubricant can be sufficiently adhered regardless of the presence or absence of scale on the surface of the workpiece, and the lubricant can be efficiently supplied to the interface between the workpiece and the guide shoe. Is possible. Therefore, the lubricant of the present invention is effective as a lubricant for various types of hot plastic working, and particularly in hot drilling of difficult-to-work materials such as steel containing 8 to 25% by mass of Cr, Furthermore, it has a great effect on preventing the occurrence of seizure flaws on the outer surface of the product.

  The excellent characteristics of the lubricant of the present invention can be sufficiently exhibited by applying the lubrication method of the present invention.

As described above, the lubricant for hot plastic working of the present invention contains 25 to 35 % by mass of iron oxide, 15 to 25 % by mass of sodium silicate, impurities are 3% by mass or less, and moisture is 42 %. A lubricant containing ˜57 mass%. Excellent lubricity is exhibited by the comprehensive action of these components. Hereinafter, each component will be described.

(1) Iron oxide:
Iron oxide is a main component for obtaining an anti-seizure effect. The iron oxide may be any of ferrous oxide (FeO), ferric oxide (Fe ₂ O ₃ ), and triiron tetroxide (Fe ₃ O ₄ ), or a mixture of two or more of these. The amount of iron oxide in the lubricant needs to be 25 to 35 % by mass. If the amount of iron oxide is less than 25 % by mass, seizure occurs between the workpiece and the member in contact therewith. On the other hand, when the amount of iron oxide exceeds 35 % by mass, the amount of iron oxide is excessive compared to the content of sodium silicate (added as a binder as described below) in the lubricant, and the lubricant becomes the workpiece. It becomes difficult to be drawn into the interface (working sliding interface) of the contact member and the surface of the tool and the tool surface, and the supply ability, which is one of the performances required for the lubricant, is deteriorated.

(2) Sodium silicate:
Sodium silicate is a binder that binds iron oxide particles, which are the main component of the lubricant of the present invention, and makes it easier for the iron oxide particles to be drawn into the working sliding interface. The amount is 15 to 25 % by mass in terms of anhydride. When the amount of sodium silicate in the lubricant is less than 15 % by mass, it is difficult for the lubricant to be drawn into the working sliding interface or the tool surface, and the supply ability necessary for the lubricant is reduced. On the other hand, if it exceeds 25 % by mass, the content of the binder is relatively excessive with respect to the main component of iron oxide, and the iron oxide seizure prevention effect is reduced.

Sodium silicate may be added as water glass. The water glass is water glass No. 1 (Na ₂ O: SiO ₂ = 1: 2), water glass No. 3 (Na ₂ O: SiO ₂ = 1: 3), water glass No. 4 (Na ₂ O: SiO ₂ = Any of 1: 4) may be used.

(3) Impurities (zinc oxide, lead oxide and copper oxide)
Although it is desirable that no impurities are contained, zinc oxide (ZnO), lead oxide (PbO) and copper oxide (CuO) are added to the iron oxide and the like in the process of preparing the lubricant of the present invention. Mixed. For example, if pickling slime or steelmaking slag in a galvanizing line is used as the iron oxide raw material, zinc oxide or the like is mixed as an impurity.

  If these lubricants are mixed in a large amount in the lubricant, when the lubricant remains on the product surface, the corrosion resistance of the product is deteriorated. Since these oxides are more easily reduced than iron oxide at a high temperature, when they remain on the product surface, they react with the steel of the product itself and deteriorate its corrosion resistance.

  As a result of elucidating the above phenomenon in detail, if the content of each of zinc oxide, lead oxide and copper oxide, or the total content of two or more of these oxides is 3% by mass or less, the effect of deteriorating the corrosion resistance Turned out to be small. Note that when the content of these oxides exceeds 3% by mass, the seizure prevention performance of the lubricant also decreases.

(4) Moisture The lubricant of the present invention contains moisture as an essential constituent. If the water content in the lubricant is less than 42 % by mass, the lubricant has a high viscosity, making it difficult to apply the lubricant to the surface of the workpiece, and it becomes impossible to ensure lubricity (seizure resistance). If the water content exceeds 57 % by mass, when the lubricant is supplied (applied) to the heated high-temperature workpiece surface, a bumping phenomenon occurs in which the water in the lubricant is vigorously steamed, and the lubricant is Scatters and does not adhere to the surface of the workpiece (particularly with first piercers where the workpiece temperature is high). By setting the water content in the lubricant to 42 to 57 % by mass, it is possible to achieve both adhesion of the lubricant and lubricity (seizure resistance) in combination with the action of each of the above components.

(5) Other components As described above, the lubricant of the present invention includes sodium naphthalene sulfonic acid soda formalin condensate, soda salt of styrene / maleic anhydride copolymer resin, polyacrylic acid soda salt, and the like. A substance that improves the dispersibility stability of the iron oxide powder, such as ether or polyethylene glycol alkylphenyl ether, may be added as a stabilizer.

  The method of supplying the lubricant of the present invention to the surface of the workpiece (usually, direct application) is not limited at all, but it is desirable to apply a spray method with good work efficiency and capable of uniform application. Since the lubricant of the present invention contains water and is in a liquid state, spray coating can be sufficiently performed.

  As described above, the hot plastic working lubricant of the present invention is excellent in lubricity (seizure resistance), and is particularly hot in difficult-to-work materials such as steel containing 8 to 25% by mass of Cr. In drilling, it is possible to prevent the occurrence of seizure flaws in the guide shoe and further the occurrence of flaws on the outer surface of the product. Moreover, the supply property which can be smoothly supplied to a required part is favorable, and the corrosion resistance etc. of a product are not impaired by the residual lubricant.

  The outer surface lubrication method in the seamless pipe production of the present invention is a lubrication method in which the above-described lubricant for hot plastic working of the present invention is directly applied to the outer surface of a workpiece immediately before piercing rolling.

As described above, the lubricant of the present invention contains moderate moisture and has excellent adhesion, so that it can be supplied to the surface of a heated high-temperature work material or other parts where it is difficult to supply the lubricant. It is. Immediately before piercing and rolling, the lubricant can be adhered to the billet surface by directly applying to the billet (workpiece) surface regardless of the presence or absence of the scale. That is, the lubricant can be efficiently supplied between the workpiece and the guide shoe . In here, "piercing and rolling just before" and refers to within one second before the start of the piercing and rolling. When the time until the start of piercing and rolling after applying the lubricant exceeds 1 second, the lubricant will be peeled off during transportation, and sufficient lubricity will not be exhibited, and there is a scale on the billet surface Since the lubricant firmly adheres to the scale, it can be a factor that causes external flaws during drilling.

  According to the lubrication method of the present invention, the excellent characteristics of the lubricant of the present invention can be exhibited sufficiently in the production of seamless pipes.

Example 1
Using a lubricant having the component composition shown in Table 1, piercing and rolling by Mannesmann-Piercer was performed. The conditions are as follows.

Work material: The material is 13% Cr, the diameter is 225 mm, and the length is 3000
Millet billet for mm oil well pipe punching machine: inclined roll type piercer guide shoe: disk roll with diameter of 2800 mm and width of 150 mm Hollow shell after drilling: outer diameter 230 mm, wall thickness 21.0 mm, length 9000 mm
Lubricant supply: Sprayed onto the surface of the work material at a discharge pressure of 0.5 MPa Note that the piercing and rolling was performed within 1 second after the lubricant was sprayed onto the surface of the work material. In Table 1, “sodium silicate” was added using water glass No. 3. The content is expressed in terms of anhydride. As "stabilizers, etc.", as substances that improve the stability of iron oxide dispersion, naphthalene sulfonic acid soda formalin condensate, styrene / maleic anhydride copolymer resin soda salt, polyacrylic acid soda salt, etc. Polyethylene glycol alkyl ether, polyethylene glycol alkyl, phenyl ether and the like were appropriately added.

  In the above drilling operation, the surface of the guide shoe was inspected after drilling to investigate the seizure status, and the supply of lubricant, the corrosion resistance of the hollow shell after drilling, and the like were investigated. The results are also shown in Table 1.

  In Table 1, the “seizure resistance” in the “test result” column was evaluated based on the surface seizure situation after drilling 50 pieces of 13Cr steel. The symbol “◯” indicates that no seizure occurred, the symbol “Δ” indicates that seizure occurred but was slight, and the symbol “X” indicates that significant seizure occurred over a wide range.

  “Corrosion resistance” was evaluated based on the corrosion area after a test piece was collected from a hollow shell after piercing and rolling and immersed in a boiling 65% nitric acid solution for 720 hours. ○ indicates that no corrosion was observed, and X indicates that it was corroded.

  “Adhesion” is an investigation item directly related to the lubricity (seizure resistance) of a lubricant used in plastic working in the hot state. The symbol “◯” indicates that the adhesion is good, the symbol “Δ” indicates that some sites with poor adhesion are observed, and the symbol “×” indicates that the adhesion is not performed.

  “Bumping property” was evaluated based on the presence or absence of intense water vaporization (bumping phenomenon) of water in the lubricant when a disk roll having a surface sprayed with a lubricant was brought into contact with the workpiece. The symbol “◯” indicates that there was no bumping, the symbol “Δ” indicates that bumping was slightly observed, and the symbol “x” indicates that there was significant bumping. When bumping occurs, the lubricant scatters and does not adhere to the surface of the workpiece, which corresponds to the evaluation of “adhesion”.

  “Fluidity” is an investigation item directly related to the quality of supply of the lubricant, and was evaluated based on the discharge state when supplying the lubricant to the surface of the workpiece by spraying. A mark ◯ indicates that the discharge state of the lubricant was good, a mark △ indicates that it was slightly worse, and a mark X indicates that the discharge was not possible.

  “Comprehensive evaluation” is an evaluation result that considers each evaluation of all items from the above “seizure resistance” to “fluidity”, where ○ mark is good, Δ mark is generally good, and X mark is poor. It represents that. In the evaluation, the worst evaluation result among the individual evaluations for all survey items was designated as “comprehensive evaluation”. For example, if one item out of all the survey items is marked with “X”, “Comprehensive evaluation” is marked with “X” even if all other items are marked with ○. Even if one of the performances (ie, lubricity, supplyability, corrosion resistance, etc.) required for the lubricant used in hot plastic working is evaluated, the lubricant is It is because it cannot be used for the use between.

  As shown in Table 1, all of the lubricants (Invention Examples 1 to 4) satisfying the conditions defined in the present invention had excellent performance and were good (◯ marks) in the overall evaluation.

  On the other hand, in the lubricant of Comparative Example 1 in which the content of iron oxide is less than the specified amount and the moisture content exceeds the specified range, bumping occurs and the lubricant does not adhere to the surface of the workpiece, and the The sticking prevention effect was not recognized.

  The lubricant of Comparative Example 2 has a slightly poor flowability (Δ mark) because the amount of iron oxide exceeds the specified amount, and smooth supply to the interface between the work piece and the guide shoe is hindered. Appearance occurred.

  In the lubricant of Comparative Example 3, sodium silicate was less than the specified amount, the water content exceeded the specified range, a slight bumping occurred, and the adhesion decreased. Therefore, seizure resistance occurred in a wide range.

  In the lubricant of Comparative Example 4, sodium silicate exceeded the specified amount, the binder content was relatively excessive with respect to the iron oxide amount, and the iron oxide seizure prevention effect was reduced.

  In the lubricant of Comparative Example 5, since the total content of impurities exceeded the specified range, corrosion occurred in the boiling 65% nitric acid immersion test of the hollow shell after piercing and rolling.

  The lubricant of Comparative Example 6 had seizure because the moisture content was slightly less than the specified range and the fluidity was lowered. Further, in the lubricant of Comparative Example 7 whose water content exceeded the specified range, bumping occurred and the lubricant did not adhere, and seizure occurred over a wide range.

(Example 2)
The lubricant according to Example 1 of the present invention shown in Table 1 is used to confirm the influence of the time until the start of piercing and rolling after the lubricant is applied to the outer surface of the workpiece on the effect of the lubricant. After the coating, the time until the start of piercing and rolling was changed, and piercing and rolling by Mannesmann-Piercer was performed in the same manner as in Example 1 except that the lubricity and the outer surface flaw of the work material (hollow shell) were The occurrence situation was investigated.

  Table 2 shows the survey results. In Table 2, the ○ mark in the “Lubricity” column is good, the Δ mark is slightly lowered, the X mark is poor, the ○ mark in the “Outer surface flaw” column is no wrinkle, and the Δ mark is slightly X indicates that a large number of wrinkles occurred.

  As shown in Table 2, when the time until the start of piercing and rolling is 0 to 1 second after spraying the lubricant onto the surface of the workpiece, it can be confirmed that both the lubricity and the outer surface defects are good. It was. However, when the time until the start of piercing and rolling exceeded 1 second, both the lubricity and the outer surface wrinkle tended to decrease, and when it exceeded 60 seconds, the lubricity was poor and a large number of wrinkles occurred on the outer surface of the hollow shell.

  The lubricant for hot plastic working of the present invention is excellent in lubricity and exhibits a remarkable effect in preventing seizure. In addition, it is excellent in supplying the lubricant to the necessary parts and does not adversely affect the corrosion resistance of the product. Therefore, it is effective as a lubricant for various types of hot plastic working, particularly in hot drilling of difficult-to-work materials such as steel containing 8 to 25% by mass of Cr, on the guide shoe, and further on the outer surface of the product. It is extremely suitable for preventing the occurrence of seizure flaws. The excellent characteristics of the lubricant of the present invention can be sufficiently exerted by applying the outer surface lubrication method in the seamless pipe production of the present invention.

  Therefore, the lubricant and the lubricating method of the present invention can be effectively used in the steel industry, particularly in the field of manufacturing seamless pipes.

Claims (1)

It contains 25 to 35 % by mass of iron oxide and 15 to 25 % by mass of sodium silicate, each content of zinc oxide, lead oxide and copper oxide, or the total content of two or more of these oxides is 3% by mass or less An outer surface in seamless pipe manufacturing, characterized in that a hot plastic working lubricant having a moisture content of 42 to 57 % by mass is directly applied to the outer surface of the workpiece within 1 second before the start of piercing and rolling. Lubrication method.